Total Number Of Tubes Research Articles

Co-delivery of VEGF and amoxicillin using LP-coated co-axial electrospun fibres for the potential treatment of diabetic wounds

Diabetic complications present throughout a wide range of body tissues, however one of the most widely recognised complications remains to be chronic diabetic wounds. Current treatment options largely rely on standard wound treatment routines which provide no promotion of wound healing mechanisms at different physiological stages of repair. Recently materials produced using novel additive manufacturing techniques have been receiving attention for applications in wound care and tissue repair. Additive manufacturing techniques have recently been used in the interest of targeted drug delivery and production of novel materials resembling characteristics of native tissues. The potential to exploit these highly tailorable manufacturing techniques for the design of novel wound care remedies is highly desirable.In the present study two additive manufacturing techniques are combined to produce a scaffold for the treatment of diabetic wounds. The combination of microfluidic manufacturing of an antimicrobial liposome (LP) formulation and a coaxial electrospinning method incorporating both antimicrobial and proangiogenic factors allowed dual delivery of therapeutics to target both infection and lack of vascularisation at wound sites. The coaxial fibres comprised of a polyvinyl alcohol (PVA) core containing vascular endothelial growth factor (VEGF) and a poly (l-lactide-co-ε-caprolactone) (PLCL) shell blended with amoxicillin (Amox). Additionally, a liposomal formulation was produced to incorporate Amox and adhered to the surface of fibres loaded with Amox and VEGF. The liposomal loading provided the potential to deliver a much higher, more clinically relevant dose of Amox without detrimentally changing the mechanical properties of the material. The growth factor release was sustained up to 7-days in vitro. The therapeutic effect of the antibiotic loading was analysed using a disk diffusion method with a significant increase in zone diameter following LP adhesion, proving the full scaffold system had improved efficacy against both Gram-positive and Gram-negative strains. Additionally, the dual-loaded scaffolds show enhanced potential for supporting vascular growth in vitro, as demonstrated via a viability assay and tubule formation studies. Results showed a significant increase in the average total number of tubes from 10 in control samples to 77 in samples fully-loaded with Amox and VEGF.

Increased preanalytical errors during Covid-19 Pandemic

The clinical laboratories worldwide have faced numerous obstacles due to the COVID-19 pandemic. In the midst of this outbreak, mistakes that occur during the preanalytical phase of sample collection, transportation, and processing can result in unfavorable clinical outcomes. Therefore, the aim of this investigation was to ascertain and contrast the rate at which blood specimens are rejected by a clinical laboratory and to analyze and compare the types of preanalytical errors during the pre-pandemic and pandemic periods. The present retrospective study was done in Chhatrapati Shivaji Subharti Hospital; India. Information was gathered from two distinct time periods - the pre-pandemic phase, which spanned from December 30th, 2019 to March 22, 2020, and the pandemic phase, which ran from March 23th to November 30, 2020. The rate of rejection for blood samples was established by determining the percentage of blood collection tubes containing preanalytical mistakes out of the total number of tubes received. A total of 102,000 blood samples were examined, out of which 40,800 (40%) were collected during the pandemic. The pandemic phase witnessed a significantly higher rate of rejection of blood samples (4%) as compared to the pre-pandemic phase (1%) (P < 0.001). In both phases, the most common preanalytical error was the clotting of samples. There was a significant increase in improperly labeled samples during the pandemic, while there was a notable decrease in hemolyzed samples. Given the prevailing situation of the Corona pandemic, altered logistics have led to a significant surge in preanalytical errors and consequent rejection of blood specimens in clinical laboratories. Therefore, it is imperative to take corrective measures at different levels to minimize preanalytical errors, which would ultimately enhance patient care and optimize the utilization of resources.

Prediction of nanofluid flows’ optimum velocity in finned tube-in-tube heat exchangers using artificial neural network

Abstract The average flow velocity in heat exchangers is considered less often and thus needs further and detailed investigation because of its crucial influence on the overall thermal performance of the application. The use of nanofluids has similar influences to finned tube designs. Considering the rise in heat transfer and pressure drop, uncertainties in cost analyses with the uses of fins and nanoparticles, evaluation of optimum operating velocity of the fluids is necessary. On the contrary, there aren’t enough experimental, parametric, or numerical investigations present on this subject. The use of machine learning techniques to heat transfer applications to make optimization becomes popular recently. In this work, important factors of the process as tube number, cleanliness factor, and overall cost as output factors have been estimated by an artificial intelligence method using 339 data points. The influence of input factors of Reynolds number, thermal conductivity, specific heat, viscosity, and total fin surface efficiency on the outputs have been studied. Total tube number, cleanliness factor, and total cost analysis have been determined with deviations of −0.66%, 0.001%, and 0.12% as a result of the solution with 6 inputs, correspondingly.

TUBES DESIGNING OF COIL-WOUND HEAT EXCHANGER

Coil-wound heat exchangers are widely used in the production of liquefied natural gas. The heat exchange surface of it is composed of concentrically wound tubes around the central core tube. The purpose of this work is to develop a method for designing the heat surface in coil-wound heat exchangers. Designing of the tube, the geometry of which is a spiral, is a laborious task. There are different types of winding depending on the size of the distance between the tubes, both in the longitudinal and radial directions. In addition, the designing should take into account the dependence between the diameter of spiral, the pitch of the spiral and the average length of the tubes in the apparatus. The developed designing algorithm, based on the iterative method of selecting the optimal option, allows getting the number of tubes in each row of winding with an equal length of tubes in all rows. The lengths of all pipes in the heat exchange zone must be equal so that the flow residence time in the tubes should be the same. Therefore, the spiral pitch on the peripheral rows should be greater than on the central ones. And the number of tubes in the peripheral rows will be greater than in the central ones too. It is proven that the angle of spiral inclination in different rows of winding should be the same. The tubes become straighter if an increase in the angle of spiral inclination and the total number of tubes is growing, but the length of each tube reduces.

Abstract WP137: Time-Course Characterization of Blood-Brain Barrier Disruption in Secondary Thalamic Injury After Stroke

Introduction: A secondary degenerative injury occurs in the thalamus after primary cortical ischemic stroke. This secondary thalamic injury progresses long-term and is associated with somatosensory dysfunctions. Blood-brain barrier (BBB) disruption is one of the feature pathological changes in primary ischemic stroke, but whether BBB disruption happens in the secondary thalamic injury is unclear. In this study, we aim to investigate the BBB changes during the development of secondary thalamic injury after stroke. Methods: Cortical ischemic stroke was generated by permanent occlusion of the left middle cerebral artery on male C57BL6J mice (12-15 weeks). BBB permeability was assessed by Biocytin-TMR (869 Da, 1mg/mL) at post-stroke days (PD) 1, 3, 7, 14, 28, 56, and 84. Immunostainings of CD68 (inflammation) and CD31 (vascular morphology) were performed. Brain sections were imaged with Confocal LSM800 and quantified by NIH ImageJ and Wimasis Image Analysis. BBB permeability related genes were quantified by real-time PCR among naïve, PD7 and PD28. Results: In ipsilesional thalamus (iTH), the Biocytin-TMR was detected as early as PD3 in the secondary thalamic injury area and persisted until at least PD84. The fluorescence intensity of Biocytin-TMR significantly increased during PD28-84 and peaked at PD56, suggesting the BBB is chronically disrupted in iTH. Compared to naïve animals, stroke animals exhibited significant increase in tube length, total number of tubes and total number of branching points at PD56 and PD84. mRNA expression of ZO-2 significantly down-regulated at PD7 and returned to baseline levels by PD28. mRNA of Angiopoietin-1 ( Ang-1 ), VEGFa and Adam10 were significantly increased at PD28. Conclusion: Our data demonstrate that the BBB disruption begins early at PD3 and continues to progress until PD84 in the secondary degenerative thalamus. This BBB disruption is accompanied by changes in blood vessel morphology and permeability related genes. Current studies are examining the expression of key genes at PD56 using qPCR and immunohistochemistry. Our results will elucidate the cellular and molecular changes of BBB disruption involved in thalamic injury, which will provide potential targets for enhancing stroke recovery.

Optimization of the finned double-pipe heat exchanger using nanofluids as working fluids

The heat exchanger pipe diameter has a significant effect on the flow characteristics as well as on the initial investment, operation and overall cost. Increasing fin dimensions increases the annulus hydraulic diameters. Even though the total volume of the heat exchanger remains unchanged between the finned and bare designs, the heat duty increases with increased heat transfer area for the finned design. The fins should be designed, and the dimensions should be calculated with special attention for different flow rates and heat exchanger dimensions. In this study, number, geometry and dimensions of the fins are determined using the algorithms available in the literature. The operational condition optimization is carried out accompanied with the cost analysis. In addition, the effects of the types of working fluids and fouled and clean cases are investigated for the total heat transfer enhancement in parallel with performance, lifetime and cost issues. A detailed analysis is presented for finned and unfinned double-pipe heat exchanger models for pure engine oil and its nanofluid mixtures with Ti, TiO2, Cu, CuO, Al and Al2O3 nanoparticles, multi-wall carbon nanotubes and graphene nanosheet having a constant particle concentration in the liquid phase. The nanofluid is flowing in annulus side, whereas the seawater is flowing in the tube side. It is observed that both the pressure drop and the pumping power increase with the increasing fin number and decrease with the cleanliness factor, whereas the total tube number decreases with increasing fin number. It is found that different types of nanofluids affect the cost and optimum annulus side velocity significantly. The results are summarized in several figures that consider the increasing Reynolds number with the cleanliness factor, the heat transfer coefficient and the pressure drop, the friction factor with changing mass flow rate and the cost values with corresponding annulus side velocities. Finally, the overall characteristics of the trend lines are provided in the figures.

Eustachian Tube Dysfunction in Children With Unilateral Cleft Lip and Palate: Differences Between Ipsilateral and Contralateral Ears.

To evaluate Eustachian tube dysfunction in the ipsilateral and contralateral ears, in children with unilateral cleft lip and palate (UCLP). Retrospective chart review. Tertiary care children's hospital. Seventy-four consecutive patients with UCLP born between 2005 and 2011 and treated at UPMC Children's Hospital of Pittsburgh Cleft-Craniofacial Center were included. Conductive hearing loss, tympanogram type, number of middle ear effusions, tympanostomy tubes, and complications. Hypothesis was formulated prior to data collection. Conductive hearing loss was nearly twice as common in the ipsilateral ear (43.2%) compared with contralateral (23.0%; P = .001, McNemar test). There were no significant differences in the frequency of each type of tympanogram between the contralateral and ipsilateral ears. The proportions of ipsilateral (90.5%) and contralateral (91.9%) ears with effusion were not significantly different. The total number of tubes received was not significantly different between the 2 ears (median of 2 bilaterally). When combined, complications (retractions, perforations, and cholesteatomas) were significantly more common in the ipsilateral ear (29.7%) compared with the contralateral ear (18.9%; P = .039, McNemar test). In children with UCLP, there were significantly more instances of conductive hearing loss and complications on the cleft side compared to the noncleft side. This suggests that Eustachian tube dysfunction may indeed be more severe on the cleft side. Considering this information, clinicians may need to be especially observant of the ipsilateral ear.

Optimum number and arrangement of evacuated-tube solar collectors under various operating conditions

Evacuated-tube solar collectors are featured by high outlet temperatures with a relatively high thermal efficiency and no direct environmental impacts. However, improper selection of the number of collectors and their arrangement, can lead to undesirable increase in the footprint and capital cost resulted from manufacturing and installation processes. The present work aims at optimizing the total number of tubes and their arrangement for large arrays of evacuated-tube collectors that are used to serve a heat driven cycle working at a relatively high inlet temperature, such as adsorption and absorption chillers and desalination systems. A deduced expression for the thermal efficiency of the evacuated-tube collector has been validated experimentally for different series and parallel arrangements. The experimental validation indicates the capability of the expression to predict the exit water temperature with a maximum relative error of 2%. Optimization charts for the optimum number and arrangement of tubes are produced at different climatic and operating conditions. Effects of the solar irradiance, mass flow rate and temperature rise on the minimum number of tubes and the corresponding arrangement are investigated and discussed. The optimization tactic used in the present study reveals that a reduction in the total number of tubes up to 41% can be achieved leading to a considerable saving in the initial cost.

Constructal design of a shell-and-tube heat exchanger for organic fluid evaporation process

A shell-and-tube heat exchanger for organic fluid evaporation process is investigated in this paper. A complex function considering the heat transfer and fluid flow performances of the shell-and-tube heat exchanger is introduced as the optimization objective. For the fixed total heat transfer area of the heat transfer tubes, structure optimizations of the shell-and-tube heat exchanger are conducted based on constructal theory. The results show that the complex function has its minimum with an optimal external diameter of the heat transfer tube. Compared the performances of the shell-and-tube heat exchanger with initial design, the total heat transfer rate, total pumping power and complex function after optimization are decreased by 7.59%, 70.65% and 11.50%, respectively. It illustrates that the complex function sacrifices a certain heat transfer performance and greatly improves the fluid flow performance, which results in an evident reduction of the complex function. Among the discussed seven working fluids, the R152a has the smallest complex function, and the R236fa has the biggest complex function. The complex function has its double minimum with an optimal mass flow rate of the hot water or an optimal total tube number. These illustrate that the overall performance of the shell-and-tube heat exchanger can be further improved by choosing appropriate working fluid, mass flow rate of the hot water and total tube number.

Condensation of R134a and R22 in Shell and Tube Condensers Mounted With High-Density Low-Fin Tubes

In this work, the condensation of refrigerants on a single, high-density, low-fin tube and full-sized shell and tube condensers were investigated experimentally. The low-fin tube had an external fin density of 56 fins per inch (fpi) and fin height 1.023 mm. Another three-dimensional (3D) finned tube was also tested for comparison. The condensing heat transfer coefficient of the refrigerant R134a was first investigated outside a single horizontal tube at saturation temperature of 40 °C. The overall heat transfer coefficients of the two tubes were similar in magnitude. The condensing heat transfer coefficient of the low-fin tube was 16.3–25.2% higher than that of 3D enhanced tube. The experiments of the two condensers mounted with low-fin and 3D enhanced tubes were then conducted in centrifugal and screw chiller test rigs. It was found that chillers with the two different condensers generally had the same refrigeration capacity under the same experiment conditions. The refrigeration capacity of the screw chiller was smaller. It had fewer tube rows and elicited fewer inundation effects owing to the falling condensate. The heat transfer coefficients of the condensers with R134a in centrifugal chillers equipped with high-density low-finned tubes were higher than those in the screw chillers. The total number of tubes for low-fin tube condensers, in the two chillers, was reduced by approximately 15% compared with the use of domestic advanced condensers equipped with the 3D enhanced tubes.

Optimal design of microtube recuperators for an indirect supercritical carbon dioxide recompression closed Brayton cycle

This paper presents a baseline design and optimization approach developed in Aspen Custom Modeler (ACM) for microtube shell-and-tube exchangers (MSTEs) used for high- and low-temperature recuperation in a 10 MWe indirect supercritical carbon dioxide (sCO2) recompression closed Brayton cycle (RCBC). The MSTE-type recuperators are designed using one-dimensional models with thermal-hydraulic correlations appropriate for sCO2 and properties models that capture considerable nonlinear changes in CO2 properties near the critical and pseudo-critical points. Using the successive quadratic programming (SQP) algorithm in ACM, optimal recuperator designs are obtained for either custom or industry-standard microtubes considering constraints based on current advanced manufacturing techniques. The three decision variables are the number of tubes, tube pitch-to-diameter ratio, and tube diameter. Five different objective functions based on different key design measures are considered: minimization of total heat transfer area, heat exchanger volume, metal weight, thermal residence time, and maximization of compactness. Sensitivities studies indicate the constraint on the maximum number of tubes per shell does affect the number of parallel heat exchanger trains but not the tube selection, total number of tubes, tube length and other key design measures in the final optimal design when considering industry-standard tubes. In this study, the optimally designed high- and low-temperature recuperators have 47,000 3/32 in. tubes and 63,000 1/16 in. tubes, respectively. In addition, sensitivities to the design temperature approach and maximum allowable pressure drop are studied, since these specifications significantly impact the optimal design of the recuperators as well as the thermal efficiency and the economic performance of the entire sCO2 Brayton cycle.

Concentration solar dryer water-to-air heat exchanger: Modeling and parametric studies

In this paper we present a modeling and parametric studies of a water-to-air heat exchanger. This exchanger is formed of a fan blowing the air to be heated through a battery of smooth tubes where the hot water—coming from solar concentrators—circulates. The heated air is injected into a thermal room to dry the clay bricks.In the first part, we study the most used models in the estimation of the heat transfer and air flow pressure drop across a tube bundle, and subsequently calculate the required transmitted power to the air.In the second part, we focus on the parametric study of the influence of the different geometric parameters of the exchanger on the heat flow rate, the air outlet temperature, the pressure drop and the requested transferred power to the air. The considered parameters are: The water heat flow rate, the heat exchanger compactness, the rows arrangement, the tube diameter, the transverse pitch, the total number of tubes, the number of rows and the air velocity.Simulations have shown that the heat exchanger performance could be improved essentially throughout the design and manufacturing process by modifying the different geometrical parameters and filling certain conditions.

Efficient hydrogen storage in up-scale metal hydride tanks as possible metal hydride compression agents equipped with aluminium extended surfaces

In the current work, a three-dimensional computational study regarding coupled heat and mass transfer during both the hydrogenation and dehydrogenation process in upscale cylindrical metal hydride reactors is presented, analysed and optimized. Three different heat management scenarios were examined at the degree to which they provide improved system performance. The three scenarios were: 1) plain embedded cooling/heating tubes, 2) transverse finned tubes and 3) longitudinal finned tubes. A detailed optimization study was presented leading to the selection of the optimized geometries. In addition, two different types of hydrides, LaNi5 and an AB2-type intermetallic were studied as possible candidate materials for using as the first stage alloys in a two-stage metal hydride hydrogen compression system. As extracted from the above results, it is clear that the case of using a vessel equipped with 16 longitudinal finned tubes is the most efficient way to enhance the hydrogenation kinetics when using both LaNi5 and the AB2-alloy as the hydride agents. When using LaNi5 as the operating hydride the case of the vessel equipped with 60 embedded cooling tubes presents the same kinetic behaviour with the case of the vessel equipped with 12 longitudinal finned tubes, so in that way, by using extended surfaces to enhance the heat exchange can reduce the total number of tubes from 60 to 12. For the case of using the AB2-type material as the operating hydride the performance of the extended surfaces is more dominant and effective compared to the case of using the embedded tubes, especially for the case of the longitudinal extended surfaces.

Optimal Design of a Multibody Self-Referencing Attenuator

The purpose of this paper is to determine the optimal size and number of tubes for a generic attenuator that is similar to Pelamis P2, the wave energy converter. Simulations using ANSYS Workbench, Design Modeler, and AQWA are performed to study the energy absorption at the nodes between the tubes. The analysis is limited to linearized hydrodynamic fluid waves loading on floating bodies by employing three-dimensional radiation/diffraction theory in regular waves in the frequency domain. Three sets of tests are conducted by varying total tube number, each tube length and the order of tubes with different lengths. After a systematic study in the frequency domain, the optimal size and number of the genetic attenuator is recommended.

2013 Late-Breaking Basic Science Abstracts

### 21998 #### Enhanced Myocardial Repair with CardioChimeras Pearl J Quijada, Jonathan D Cubillo, Claudio Staub, Mark A Sussman; San Diego State Univ, San Diego, CA Dual stem cell transplantation of c-kit positive cardiac progenitor cells (CPCs) and mesenchymal stem cells (MSCs) after infarction support modest improvements in cardiac function, however there are currently no reports substantiating a single stem cell type supporting both direct and indirect mechanisms of myocardial repair. Therefore we created a CardioChimera, a stem/progenitor cell formed by fusion between CPCs and MSCs, resulting in a unique progeny superior to either individual precursor. CardioChimeras were purified after cell fusion with Hemagglutinating virus of Japan and expanded clonally based on dual expression of fluorescent proteins mCherry and eGFP from CPCs and MSCs respectively. CardioChimeras are mono-nucleated, have comparable growth kinetics to parental CPCs and MSCs and display increased cellular size unrelated to cell cycle arrest and/or senescence. CardioChimeras have increased expression of cardiomyogenic lineage markers cardiac troponin T (2.5-fold), smooth muscle 22 (9.3-fold), and CD31 (10.7-fold) concomitantly associated with decreased c-kit protein expression (50%) relative to parent CPCs. Lineage commitment of CardioChimeras is bolstered by dexamethasone treatment measured by mRNA levels of cardiogenic genes and increases in active mitochondria (2.2-fold) after labeling with MitoTracker. Induction of apoptosis is blunted in cardiomyocytes co-cultured with CardioChimeras compared to co-culturing with CPCs and MSCs alone, or combination of non-fused parent cells. CardioChimeras enhance cardiomyocyte growth similar to parent MSCs owing to an increased propensity to secrete pro-growth factors. Collectively, CardioChimeras represent an adaptable cell therapy combining the beneficial properties of CPCs to undergo cardiac specific commitment as well as MSCs that foster an improved microenvironment with protective paracrine secretion. Clinically, CardioChimeras merge the application of distinct cell types into a single entity for increased engraftment, mitigation of inflammation and blunting the progression of heart failure by promoting myocardial regeneration. …

Cuff Inflation-Supplemented Laryngoscope-Guided Nasal Intubation

Softer endotracheal (ET) tubes are more difficult to navigate in the oropharynx than the stiffer polyvinyl chloride (PVC) tubes during nasotracheal intubation (NTI). Cuff inflation has been used to guide PVC tubes into the laryngeal inlet during blind NTI, but it has not been tested when performing NTI under direct laryngoscopic guidance. We assessed the role of cuff inflation in improving oropharyngeal navigation of 3 ET tubes of varying stiffness during direct laryngoscope-guided NTI. Simultaneously, we also assessed and compared the nasotracheal navigability and incidence of nasal injury with these ET tubes during cuff inflation-supplemented, laryngoscope-guided NTI. One hundred sixty-two adults were randomized to undergo NTI with either a conventional PVC (n = 54), wire reinforced (WR; n = 54) or a silicone-tipped WR (SWR; n = 54) ET tube. Ease of insertion of these tubes was assessed during passage from nose into oropharynx, from oropharynx into laryngeal inlet aided by cuff inflation if needed, and from laryngeal inlet into trachea. Nasal morbidity was assessed by a blinded observer. All ET tubes could be inserted into the trachea. Seventy-one of 162 ET tubes could be inserted from the oropharynx into the laryngeal inlet without cuff inflation. Eighty-six of the remaining 91 tubes that did not enter the laryngeal inlet without cuff inflation could be inserted when using the cuff inflation technique. Thus, a total of 157 ET tubes could be inserted into the laryngeal inlet with cuff inflation (95% confidence interval of difference of proportions between total number of tubes passed [157] and those without cuff inflation [71]: 53% [45%-61%]). The remaining 5 tubes had to be inserted with the help of Magill forceps. The incidence of epistaxis was lowest with the SWR tube (difference of proportions [95% confidence interval] SWR versus PVC 27% [8%-45%]; SWR versus WR 20% [1%-38%]; WR versus PVC 7% [-12% to 26%]). The cuff inflation technique consistently improved the oropharyngeal insertion of the 3 ET tubes of varying stiffness during direct laryngoscope-guided NTI. Supplemented with the cuff inflation technique, the SWR ET tube seems to be better than the PVC and WR ET tubes in terms of complete nasotracheal navigability and less perioperative nasal injury.

Volumetric mapping of tubeworm colonies in Kagoshima Bay through autonomous robotic surveys

We developed and tested a comprehensive method for measuring the three-dimensional distribution of tubeworm colonies using an autonomous underwater vehicle (AUV). We derived volumetric measurements such as the volume, area, average height, and number of tubes for colonies of Lamellibrachia satsuma, the world's shallowest-dwelling vestimentiferan tubeworm discovered at a depth of 82 m, at the Haorimushi site in Kagoshima Bay, Japan, by processing geometric and visual data obtained through low-altitude surveys using the AUV Tri-Dog 1. According to the results, the tubeworm colonies cover an area of 151.9 m 2, accounting for 5.8% of the observed area (2600 m 2). The total number of tubes was estimated to be 99,500. Morphological parameters such as area, volume, and average height were estimated for each colony. On the basis of average height, colonies could be clearly separated into two groups, short (0.1–0.3 m) and tall (0.6–0.7 m), independent of the area.

Quantitative Diffusion Tensor Imaging Tractography Metrics are Associated with Cognitive Performance Among HIV-Infected Patients

There have been many studies examining HIV-infection-related alterations of magnetic resonance imaging (MRI) diffusion metrics. However, examining scalar diffusion metrics ignores the orientation aspect of diffusion imaging, which can be captured with tractography. We examined five different tractography metrics obtained from global tractography maps (global tractography FA, average tube length, normalized number of streamtubes, normalized weighted streamtube length, and normalized total number of tubes generated) for differences between HIV positive and negative patients and the association between the metrics and clinical variables of disease severity. We also examined the relationship between these metrics and cognitive performance across a wide range of cognitive domains for the HIV positive and negative patient groups separately. The results demonstrated a significant difference between the groups for global tractography FA (t = 2.13, p = 0.04), but not for any of the other tractography metrics examined (p-value range = 0.39 to 0.95). There were also several significant associations between the tractography metrics and cognitive performance (i.e., tapping rates, switching 1 and 2, verbal interference, mazes; r > or = 0.42) for HIV infected patients. In particular, associations were noted between tractography metrics, speed of processing, fine motor control/speed, and executive function for the HIV-infected patients. These findings suggest that tractography metrics capture clinically relevant information regarding cognitive performance among HIV infected patients and suggests the importance of subtle white matter changes in examining cognitive performance.

The Effect of Novel Plasma-Coated Compact Tube Bundles on Pool Boiling

Boiling heat transfer of R-134a on a porous, plasma-coated tube bundle was investigated experimentally to determine the effects of the number of tube rows and the total tube number. The bundle consists of up to four tubes with a pitch-to-diameter-ratio of 1.33. Heat transfer coefficients for a single tube with a porous copper coating were up to four times higher than for a smooth tube. Observations showed that the plasma coating enhanced the heat transfer coefficient in tube bundles as well. The bundle factor of the coated tube bundle showed a similar, slightly increased trend as the smooth tube bundles. The enhancement effect of the coated tubes decreases to a certain extent with an increasing heat flux and decreasing saturation temperature. However, it is significantly less pronounced than trends that have been reported from other investigations. The aim of a stable enhanced coating was confirmed by long-term experiments with steady results.

Hysterosalpingo-Contrast Sonography Compared with Hysterosalpingography and Laparoscopic Dye Pertubation to Evaluate Tubal Patency

Study Objective To evaluate the advantages and accuracy of hysterosalpingo-contrast sonography (HyCoSy) in assessing tubal patency compared with hysterosalpingogram (HSG) and laparoscopic dye pertubation. Design Prospective study (Canadian Task Force classification II-2). Setting Obstetrics and Gynecology Department, University of Rome Tor Vergata. Patients Twenty-three women with at least 1 year of infertility, and 15 women with a history of chronic pelvic pain, suspected endometriosis, or pelvic inflammatory disease (PID), or with sonographic markers of adhesions. Intervention HyCoSy, HSG, and laparoscopic dye pertubation. Measurements and Main Results All patients underwent HyCoSy during the proliferative phase using air with saline as contrast medium, and HSG within 1 month of HyCoSy. Laparoscopy and dye pertubation were performed only in women with chronic pelvic pain, suspected endometriosis, PID, and sonographic markers of adhesions. In women undergoing all three procedures, HSG and HyCoSy had the same high concordance as laparoscopy, 86.7% and 86.7%, respectively. Three women in the infertility group became pregnant immediately after HyCoSy and dropped out of the study. In one woman, HyCoSy could not be performed because of cervical stenosis. Considering the total number of tubes (67), concordance between HyCoSy and HSG was 89.6%. Conclusion Transvaginal HyCoSy using a combination of air and saline appears to be an inexpensive, fast, and well-tolerated method of determining tubal patency. One of the most important advantages of this technique is, in our opinion, the possibility of obtaining information on tubal status and the uterine cavity at the same time as conventional ultrasound scan is performed.